China Friday raised the alert for floods to the highest level as heavy rains pounded the central and southern provinces, forcing the evacuation of more than half a million people, a media report said.Over 555,000 people were evacuated from their homes in seven provinces after rains caused havoc in the Yangtze river basin. A prolonged drought had earlier gripped the region, the report in China Daily said. At least 19 people were killed in incidents caused by rains in the past four days in the provinces of Anhui, Zhejiang, Jiangxi, Hubei, Hunan, Sichuan and Guizhou provinces. The government Friday raised its alert to the highest level of four. It described the floods in some areas as the worst since 1955. According to the official toll, at least 105 people were killed in floods and mudslides since June 3.